Rotary bit.



E. DOUBLE.

ROTARY BIT.

APPLICATION F|LD1uNE8.19|4.

Patented May 1, 1917.

EDWARD DOUBLE, or Los ANGELES, cALrEonNrA.

Borana' Brr.

Specication of Letters Patent.

rammen may i, asia Application led June 8, 1914. SeraI No. 843,708.

To all whom t may concern:

Be it known that I, EDWARD DOUBLE, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented a new and useful Rotary Bit, of which the following is a specification. 0

This invention relates to a rotary drilling bit in which a plurality of rotating cutters is employed, and the main object of the invention is to provide means for securelyretaining the cutters and permit them to be readily removed when desired. The cutters are mounted on studs which are screwed into the body of the bit at the lower end thereof, which lower end is tapered in order to support the cutters at the proper angle, and there is not much metal in the tapered portion of the body in which to screw the said studs. 1n the present invention, l provide a bolt which extends longitudinally through the studs, and which is drawn tight to grip and securely hold the studs in position. By removing this bolt, which may be very easily done, as both of its ends are accessible in the outer ends of the studs, both cutters may be quickly removed for sharpening or replacement. ln operation, as the body of the bit rotates clockwise, it produces a motion of the cutters in addition to their bodily rotation. This bodily loosen the supporting studs.

rotation of the cutters is obviously clockwise, but their individual axial rotation is counter-clockwise. This counter-clockwise movement would have a tendency to unscrew the supporting studs during the cutting operation were the studs provided with a right hand thread, and to prevent this, the studs are provided with a left hand thread, so that the rotative action of the cutters during the cutting operation will have a tendency to tighten rather than However, in backing olf the drill where a reverse rotation is given to the cutters, this has a tendency to unscrew their supporting studs and the present invention thus provides a positive means for retaining the studs under all conditions of use.

Referring to the drawings:

Figure 1 is a side elevation of the bit.

Fig. 2 is a longitudinal section through the bit takendiametrically through the cutters; and

F ig. 3 is a bottom plan view of the body of the bit.

1 designates the body of the bit, which and with a threaded end 3 for attachment to a socket, not shown. The lower end of the body has a tapered end 4 with threaded sockets 5 in opposite portions to receive the threaded ends of' studs 6 having heads 7. Bushings 8 are mounted on the studs 6, and cutters 9 are mounted on the bushings 8. Each cutter 9 may be of any preferred construction, as herein shown. The cutter consists of a disk, the convex outer face having a. cutting edge 10. Washers 11 are arranged between the bushings and tapered portion 4, and washers 12 are arranged between the heads 7 and bushings 8 and cutters 9.

Each stud 6 is hollow and extending through the tow studs is a bolt 13, each of the studs having a conical recess 14 to give room for the curvature of the bolt 13. The heads 7 of the studs are slotted at 15 to enable them to be screwed in position, and the conical bores 14 of the studs obviate the necessity of fixing the studs at any delinite angle into rotative position, and permits each of the studs to be screwed tightly into position, after which the bolt 13 is inserted and the nuts 16 screwed tight. The heads Z are provided with sockets 17 to receive the nuts 16 of the bolt.

The bushing 8 is provided with an annular lubricant recess 19 and with a series of radial lubricant passages 20 for conducting oil to the bearing surface of the cutter. The bushing is also provided with passages which may be closed by corks 21 after the recess 19 is filled with oil. Branch water course passages 22 lead from the water course 2 and have discharge mouths 23 on opposite sides of the tapered portion 4 between the two cutters, as shown in Fig. 1. With the construction thus provided, it is impossible for the studs to unscrew and lose the cutters.

What I claim is:

1. In a rotary bit, a body having a tapered end, a pair of studs screwed into opposite faces of said end, rotary cutters mounted on said studs and a bolt, the end portions of which are in substantial alinement with the longitudinal axes of the studs, said bolt passing longitudinally through said studs and securing the same to the body, eachof said cutters having a tapered bore to allow the passage of the bolt irrespective of the angular rotative position `of the stud.

2. In a rotary bit, a body having a tapered end, a plurality of studs, screwed in opposite faces of said end, each of said studs having a head, a bushing on each stud, a rotary cutter mounted on each bushing and retained by the head of the stud, said studs being hollow, and a bolt passing longitudinally through both of said studs and through the body to positively retain the studs on the body, a washer between each cutter and the tapered end portion, and a washer between each cutter and the adjacent head of the stud, each of said bushings having a lubricant chamber with lubricant ducts leading from said chamber to the bearing surface of thebushing.

3. In a rotary bit, a body having a tapered end, a plurality of studs screwed in opposite faces of said end, each of said studs having a head, a bushing on each stud, a rotary cutter mounted on each bushing and retained by the head of the stud, said studs being hollow, and a bolt passing longitudinally through both .of said studs and through the body to positively retain the -studs on the body, a washer between each cutter and the tapered end portion, and a washer between each cutter and the adjacent head of the stud, each of said bushings having a lubricant chamber with lubricant ducts leading from saidchamber to the bearing surface of the bushing, each of said bushings being provided with a filling passage leading to the lubricant chamber.

4. In a rotary bit, a body, a-pair of headed studs having bores formed longitudinally therethrough secured upon opposite sides of the body near the lower end thereof, rotary cutters mounted on said studs and held in place by the heads thereof, and a bolt insei-ted through the studs and body and having its ends located within the bores in said studs, said studs being located in outwardly and downwardly inclined planes relatively to the longitudinal axis of the body and having their bores uniformly enlarged at their inner ends to allow the passage of the bolt therethrough irrespective of the angular rotative positions of the studs.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 30th day of May, 1914.

EDWARD DOUBLE.

In presence of FREDERICK S. LYON, LORRAINE E. DURRow. 

